Arbeitsbericht NAB 19-12

This manual is intended to provide background information for recording and describing deformation structures in drill cores from Nagra's drilling projects. The purpose of this instructional manual and the associated factsheets shall ensure consistency for core dewscriptions of different individuals. The documents include a concise list of structures to be used. Names of structures are based on accepted definitions published in peer-reviewed literature (see chapter 10). This manual, however, is not intended to inform geologists regarding the geotechnical core inspection, but rather provide field personnel with a brief overview of the different deformation structures in drill cores and definitions of structure types to be used during core inspection for Nagra. All parameters necessary with regard to a standard procedure for core inspection are characterised.

In particular, this manual focuses on brittle deformation structures in sedimentary rocks such as mudstone, marl and limestone of the Swiss Jura Mountains. The drill cores may also contain a limited suite of ductile structures such as shear bands and pressure solution surfaces. These ductile structures are briefly described. However, this manual is not meant to be applied to structures developed by ductile deformation.

This manual outlines a standard procedure for describing structural records on newly recovered core material. A flowchart (see appendix A) helps to distinguish clearly between the different deformation structure types.